On August 26, prosecutors in Chiayi indicted three former employees of Co-Tech Development Corp. (8358.TWO), a leading supplier of electrolytic copper foil used in printed circuit boards and high-frequency applications, for allegedly leaking trade secrets to a technology firm in mainland China, marking one of the most serious intellectual property theft cases in Taiwan's materials sector in recent years.

According to investigators, a former plant director surnamed Lin and production supervisor surnamed Lu were recruited with high salaries by Zhongcheng Caihong, a company in mainland China. They later persuaded three other Co-Tech staff—including a manufacturing supervisor surnamed Chen, an assistant engineer surnamed Chang, and a deputy process manager surnamed Lin—to join them. The trio allegedly copied confidential data onto USB drives or photographed documents containing product formulas, process know-how, and equipment specifications, which were then transferred to the mainland China company.

Authorities said the stolen data involved key copper foil technologies developed with more than NT$350 million in R&D investment. Products tied to the leaked information account for nearly half of Co-Tech's revenue, generating operating profits of around NT$600 million annually. Prosecutors have charged Chen, Chang, and Lin under Taiwan's Trade Secrets Act, while the two senior managers who defected to mainland China remain at large.

Co-Tech confirmed the incident and emphasized that its layered management system, patent portfolio, and internal monitoring mechanisms helped detect the breach early. The company said it promptly launched legal action and cooperated with law enforcement to prevent further damage.

“This product line has long been certified by our customers, and each stage of production contains unique technical know-how that cannot be easily replicated by competitors,” Co-Tech said in a statement. “We will continue to advance our HVLP4 copper foil technology and strengthen protection through both trade secrets and patents, ensuring long-term competitiveness and stability.”

The company noted that it holds multiple invention patents across Taiwan, the United States, Japan, and mainland China, underpinning its global strategy and sustainable development despite the ongoing investigation.